Updated: 4:46 p.m. | There's no guarantee this is Minority Leader Nancy Pelosi's last term in office but should she retire in 2016, House Democrats will be using plenty of metrics to pick her successor — and the upcoming trade vote could be one of them.

Trade Promotion Authority — the vote could come as soon as this week — has support from President Barack Obama, most Republicans and a handful of pro-trade congressional Democrats. On the other is a largely united, and increasingly fiercely opposed, Democratic Caucus.

And Democrats with an eye for the top spot seem to know it.

When Minority Whip Steny H. Hoyer was asked Tuesday how the trade vote could affect positioning among House Democrats if Pelosi were to leave, Hoyer didn't deny the TPA vote could play a role in a leadership race.

"My vote's going to be made on the substance of what I believe, and not on any ramifications that it might have," Hoyer told reporters at his weekly pen-and-pad briefing. "That doesn't mean it doesn't have ramifications. I presume it does."

Hoyer, who would run to succeed Pelosi as minority leader if given the opportunity, would not say Tuesday how he would vote.

A vote for TPA wouldn't necessarily preclude a Democrat from winning a leadership race down the line — support for fast-track authority could always be sold as support for the president, a display of party loyalty that could go a long way.

If Rep. Debbie Wasserman Schultz, D-Fla., votes for TPA, that could be her argument. (She’s in something of a difficult spot as a member of the moderate and largely pro-trade New Democrat Coalition and, above all else, the chairwoman of the Democratic National Committee.)

There is also presently no concrete evidence that House Democrats are intent on using the trade vote as their barometer for choosing any future member of the leadership slate. Still, TPA is already becoming a litmus test for ideological purity, with the majority of House Democrats under political and social pressure to oppose it.

The AFL-CIO is has frozen congressional campaign contributions until after the vote on final passage of TPA and is intent on taking down House Democrats who have said they'll vote "yes," such as vulnerable incumbent Reps. Ami Bera, D-Calif., and Kathleen Rice, D-N.Y., who over the weekend said that while she was originally a "no," she'd come to reverse her position.

Rep. Alan Grayson, D-Fla., last week sent a letter to supporters urging them to contact his Democratic colleagues who favor TPA in order to "air grievances." Even though it might have violated House ethics rules, Grayson included their office contact information.

The debate has become so fractious it's possible "yes" votes could come back to haunt aspiring House Democratic leaders, especially if an opening for minority leader occurs next year when the issue is still so fresh in members' minds. The Congressional Progressive Caucus is also currently the largest contingent of House Democrats, and they will undoubtedly be looking to replace Pelosi — should the job come open — with a liberal stalwart.

Progressives on and off Capitol Hill have praised Rep. Joseph Crowley, D-N.Y., for moving farther to the left over the past few years. (Crowley says he'll vote against TPA.)

He is being termed-out at the end of 2016 as the vice chairman of the House Democratic Caucus and there's no question he's looking to move up, either to chairman of the full caucus or something even bigger.

Outgoing Caucus Chairman Xavier Becerra, D-Calif., would have voted "no" anyway as a reliably progressive voter, but his opposition at this point is also significant. He'll be a man without a seat at the leadership table at the end of next year due to term limits.

In many ways, the TPA vote loses significance as a test of leadership if every Democratic contender for the top spot votes no. But leaders have already shown many of their cards. While Obama continues to insist TPA would be a positive step forward, not to mention a significant second-term achievement, House Democratic leaders have sat on the sidelines, neither really pushing for or against the trade legislation.

While some Democrats, such as Grayson, can shore up their progressive bona fides by coming out in full force against the trade deal, most Democrats in positions of power have settled for a type of detente with the president. They are neither whipping for nor against TPA.

Certainly, however, the issue has caught the attention of the Democratic Caucus, and outside Democratic groups. Everybody is watching — and everybody knows it.

And in the meantime, Pelosi spokesman Drew Hammill suggested this whole conversation was irrelevant.

“Leader Pelosi has always said she’s here on a mission, not a shift," he said.